Page 258 - parasitology for medical and clinical laboratoryprofessionals

238 CHAPTER 11

such as fever, headache, fatigue, and muscle and joint Organ failure may follow, including adult respiratory dis-
aches. Because the organisms infect red blood cells, ane- tress syndrome (ARDS).
mia sometimes occurs as a result of the lysis (destruction) Under what conditions is babesiosis most often dis-
of red blood cells. This is a condition that frequently covered and when is it usually diagnosed? When an illness
leads to enlargement of the liver and spleen (hepato- and strikes with certain symptoms and signs in an endemic
splenomegaly), as these organs are in part responsible for area of the country, the physician may suspect babesiosis
removing infected blood cells from the body along with and will request appropriate blood tests to determine if
broken down and damaged red blood cells. the patient has been exposed to this illness. Some people
The risk of becoming severely ill and dying is in- with babesiosis will sometimes suffer from an additional
creased in people who have had their spleen removed tick-borne illness such as Lyme disease. Sometimes the
as well as those who take illicit or immunosuppressive infection is discovered accidentally when the physician
drugs. For those who have accompanying disorders has asked to have other blood tests performed that are
that tend to weaken the immune system, particularly for unrelated to tick-borne illnesses but to diagnose other
those suffering from AIDS, an increased risk of mortal- medical conditions that exist or when other tick-borne
ity appears. In this group of victims, babesiosis may also illnesses are suspected. Remember that symptoms and
resemble malaria by causing episodes of cyclical high signs of babesiosis may be so mild as to be unnoticed by
fever, accompanied by anemia, dark urine, and jaundice the victim.
or yellowing of the skin from liver damage and kidney
failure. The disease of babesiosis is transmitted by the Diagnosis of Babesiosis
same type of deer ticks of the family Ixodidae that also Babesia may not be observed in a blood smear unless
transmits the organism causing Lyme disease. Again, this the laboratory professional is particularly astute, or is
infection is common among animals but is somewhat looking for intracellular parasites of the blood. To diag-
rare and may even be asymptomatic in humans except nose babesiosis, a laboratory technician, technologist,
for those with immune system disorders. or parasitologist will examine a stained blood sample
as a stained smear using a microscope. Both thick and
Symptoms of Babesiosis thin blood smears are stained with a special stain called

Most patients with Babesia infections are asymptomatic Wright’s-Giemsa for the microscopic examination
or only experience mild fevers and slight anemia that (Figure 11-14). But frequently treatment is not necessary
go virtually unnoticed. Babesiosis can afflict people of for a mild infection in healthy people with a functioning
all ages, but most people who contract the disease are spleen and who do not have other predisposing factors,
in their 40s or 50s. Some people who contract babe- as the infection typically is resolved on its own.
siosis may not have any symptoms and will later have
no knowledge of having been infected. Most of these
patients will recover spontaneously without treatment.
However, in certain circumstances where the health of
the individual is compromised, as in patients with an im-
munodeficiency such as HIV/AIDS, and in the elderly
and the very young, the illness can quickly become se-
rious. The disease can even cause death, especially in
people who have had their spleen removed or who have Source: Centers for Disease Control and Prevention (CDC)
weakened immune systems.
Symptoms in the more severe cases will include
fever with temperatures rising as high as 104°F, ac-
companied with chills, sweating, weakness, tiredness,
joint and muscle aches, poor appetite, and headaches.
In extremely severe cases there are symptoms similar FIGURE 11-14 Giemsa-stained slide depicts an
to malaria, with fevers rising to 105°F/40°C, shaking example of properly prepared thick and thin film blood
chills, and severe anemia from red blood cell destruction. smears to be examined